Oil sands are a mixture of sand, water, clay and bitumen. Bitumen is oil that is too heavy or thick to flow or be pumped without being diluted or heated. At 10° C/50° F, bitumen is hard as a hockey puck. Some bitumen is found within 70 metres (200 feet) of the surface, but the majority is deeper underground.
Bitumen is so viscous that at room temperature it acts much like cold molasses. A variety of treatment methods are currently available to oil sands producers and new methods are put into practice as more research is completed and new technology is developed.
Oil sand can be found in several locations around the globe, including Venezuela, the United States and Russia, but the Athabasca deposit in Alberta is the largest, most developed and utilizes the most technologically advanced production processes.
Alberta's oil sands lie under 142,000 km2 of land (54,800 mi2). Only about three per cent, or 4,800 km2 (1,850 mi2), of that land could ever be impacted by the mining method of extracting oil sands. The remaining reserves that underlie 97 per cent of the oil sands surface area are recoverable only by in-situ (drilling) methods, which require very little surface land disturbance. The oil sands area actively being mined is 904 km2 (346 mi2), an area slightly larger than the City of Calgary.
Oil sands or tar sands?
Historically, oil sand was incorrectly referred to as tar sand due to the now outdated and largely ineffective practice of using it for roofing and paving tar (oil sand will not harden suitably for these purposes). Though they appear to be visibly similar, tar and oil sands are different; while oil sand is a naturally occurring petrochemical, tar is a synthetically produced substance that is largely the last waste product of the destructive degradation of hydrocarbons. Furthermore, their uses are completely different: oil sand can be refined to make oil and ultimately fuel, while tar cannot and has historically been used to seal wood and rope against moisture. Source: Alberta Energy